FR2681597A1 - ESTERS OF POLYBASIC ACIDS USED AS CORROSION INHIBITORS IN PETROLEUM FIELDS. - Google Patents

Abstract

A corrosion inhibitor having excellent film formation and persistence characteristics can be produced by first reacting in a condensation reaction a polybasic acid with a polyalcohol to form a partial ester. The partial ester is reacted with an imidazoline and / or fatty diamines to salify the ester. If required, the salified partial ester can be reacted with a metal hydroxide, a metal oxide and / or ammonia to further salify the ester. Surfactants can be added to tailor the inhibitor formula to the specific needs of the user (i.e., the corrosion inhibitor can be formulated to produce a highly dispersible corrosion inhibitor in water soluble in petroleum or a corrosion inhibitor soluble in water and dispersible in petroleum). Suitable vehicle solvents can be used, if necessary, to effectively disperse the corrosion inhibitor formula.

Description

J 2681597

  Esters of polybasic acids used as corrosion inhibitors in oil fields This invention aims to inhibit the corrosion of metals used in oil fields where hydrocarbons and water are taken from production wells Water can cause corrosion of metal tubes, etc., which are used in wells It is therefore necessary to add an appropriate agent to the mixture of petroleum and water to effectively reduce or eliminate the problems associated with corrosion of metallic parts. Failure to do so may result in extensive corrosion of metals in these oil fields, this corrosion leading to repairs

  costly and lost productivity.

  The petroleum industry has traditionally used corrosion inhibitors based on petroleum soluble dimer acids to reduce corrosion in oil well casings. These inhibition formulas include

  commonly substances that are produced by condensa-

  thermal tion of fatty acids with 18 functional carbon atoms-

  nalized (containing one or two double bonds, for example oleic and linoleic respectively) Examples of

  well known methods for carrying out the polymerization

  The thermal action of fatty acids consists, inter alia, in heating a mixture of suitable fatty acids (for example a tall oil fatty acid or a soy fatty acid) in the presence of a clay or other suitable catalyst for obtain variable amounts of fatty acids with 36 carbon atoms (dimerized) and 54 carbon atoms (trimerized) These dimeric fatty acids and / or trimers are neutralized with a fatty acid imidazoline derived from an appropriate amine (generally a diethylene triamine or DETA) to obtain a corrosion inhibitor These inhibitors are soluble in petroleum with minimal dispersing power in water and they act by covering the metal surfaces (by adsorption by polar groups), thus excluding water which is necessary for the corrosion process to take place. However, in recent years, several factors have led the petroleum industry to reassess its traditional preference for water-dispersible and oil-soluble corrosion inhibitors. Many oil wells commonly produce mixtures with grades

  in water higher than their petroleum content We can improve

  rer yield using the majority fluid in these wells as a vehicle for the inhibitor In addition, water (and dissolved earth minerals) is the fluid that causes electrochemical corrosion in oil and gas pipelines If we could actually break the corrosion cycle at its source, we would have a more effective inhibitor Finally, the vehicle solvent constitutes approximately 70% of a standard corrosion inhibitor mixture Replace traditional heavy aromatic naphthas and other hydrocarbon solvents with water would eliminate environmental damage caused by the use of solvent-based

  hydrocarbons, while also reducing costs.

  Thus, the trend that is developing in the petro-

  The path is to move from petroleum-soluble supply systems for corrosion systems to water-soluble supply systems. This is evidenced by the growing number of companies that require testing of corrosion inhibitors by devices. of linear polarization resistance measurement (which control inhibition in pure aqueous systems rather than in

  traditional systems based on hydrocarbons and water).

  In order to increase their dispersing power in water, conventional petroleum soluble dimer / trimer mixtures have been formulated with both fatty acid imidazolines and various surfactants. However, the scope of this approach is is found to be limited The use of sufficient surfactant to make

  water soluble the dimer / trimer molecule severely reduced-

  ment the formation and the persistence of the film In other words, the corrosion inhibitor simply rinses the metal, leaving it unprotected Furthermore, these mixtures made highly surfactant tend to emulsify under the conditions prevailing in the wells, which causes problems

important to the user.

  Commonly available water-soluble corrosion inhibitors include quaternary alkylated pyridine compounds (usually benzyl quaternary compounds), imidazoline salts (with acetic acid), and imidazoline ethoxylates. have been used to a limited extent in gas and oil pipelines, they have not yet been found to be sufficiently tenacious to satisfactorily inhibit corrosion when used under the dynamic conditions prevailing in the

oil well in production.

  It is therefore the object of this invention to provide an effective and economical corrosion inhibitor which can be used in oil fields, which can be manufactured either as a highly water-dispersible molecule or as a molecule soluble in water. water These molecules can be formulated to provide petroleum soluble and highly dispersible in water corrosion inhibitors or petroleum soluble and water soluble corrosion inhibitors, based on the specific individual needs of the user Other goals, characteristics and advantages will become apparent on reading the

following description.

  The object of this invention is achieved by first reacting in a condensation reaction a polybasic acid with a polyalcohol to form a partial ester This partial ester is reacted with an imidazoline and / or fatty diamines to form a salt If necessary , the ester

  partially transformed into salt can be partially or total-

  Neutralized by metal hydroxide, metal oxide and / or ammonia Surfactants and / or a suitable vehicle solvent can be added to produce a corrosion inhibitor formula, which is either petroleum soluble and very dispersible in water, either dispersible in petroleum and soluble in water, in

  according to user requirements.

  The background conditions in an oil or gas well can vary greatly from one well to another. In other words, the environment can be "non-sulfurous" (CO 2) or "sulfurous" (H 2 S), water to oil reports can

  vary and the mineral content of water may also vary.

  However, the above corrosion inhibitors can be formulated to meet the specific requirements of

  these various environments In addition, inhibitors conserve

  wind their ability to form protective films with excellent persistence on metal surfaces under a

wide spectrum of conditions.

  Traditionally, those skilled in the art have generally accepted

  that the protection against corrosion is adequate

  the concentration of the imidazoline carboxylate in the inhibitor In the case of partial acid esters

  polybasic described here, for equivalent concentrations

  tes, the imidazoline carboxylate concentration is reduced by a percentage of up to 50% and yet the corrosion protection is equal to or greater than that of analogous formulas based on polybasic acid and imidazoline having total concentrations of equal components. In fact, the partial esters of polybasic acids thus formulated have both a greatly improved dispersing power or a water solubility and a

  improved corrosion inhibitor (i.e. persistence

  film) compared to industry standard corrosion inhibitor formulas (both oil soluble and water soluble) In addition, the dosage required to provide the industry standard for protection against corrosion of 90% or more is reduced significantly.

  We will now describe the preferred embodiment.

  The polyvalent corrosion inhibitor molecule can be represented by the following chemical structures:

A) CH 3 (CH 2) 5 () OR

CH 3HCHZ) C OR

  (CH 2), (c E%; 7 I O-Z + O B) CH: H (2) 5 (C;) 7 C z +

(CH 2) 5 (C 2) 7

  CH 3 OR in which R is a polyalcohol (or combinations of polyalcohols) and Z + is imidazoline and / or fatty diamines. In a preferred method of producing the corrosion inhibitor, one or more polybasic acids are first reacted (in a condensation reaction) with one or more polyalcohols to form a partial ester with a low acid number (c (i.e. 15 to 155) The partial ester is reacted with imidazoline and / or fatty diamines to form a salt. The salified ester obtained can be reacted with a metal hydroxide, a metal oxide and / or ammonia to further salify the ester. Various surfactants can be added to obtain an inhibitor formula suitable to meet the needs of the user. If necessary, an appropriate carrier solvent can be used to disperse the corrosion inhibitor. The final water solubility of the corrosion-inhibiting ester (whether dispersible in water or soluble in water) will depend on the degree of both the esterification and

  salification of the molecule, the quantity and the character

  tere surfactants added to the formula and the amount and character of the vehicle solvent used The molecular weight and hydrophilic nature of the polyalcohol

  reaction largely determine the resulting degree of esteri-

  cation In the present invention, the corrosion inhibitor ester has an esterification range between 35 and

  71%, the preferred range being 45 to 60% The degree of salifica-

  tion of the molecule is directed by the choice of the amine (that is to say its hydrophilic / hydrophobic nature), of the metal or of the ammonia derivative used here, a range of 15 to 32% by weight of the molecule is salified with an imidazoline, fatty diamines or combinations of these substances (the preferred range being 18 to 28% by weight) This salified ester can then react with 5 to 10% by weight of a metal hydroxide, a metal oxide, ammonia or their

  combinations to further salify the molecule.

  Polybasic acids suitable for use in the production of the inhibitor include dimerized fatty acids of 16 to 36 carbon atoms, trimerized fatty acids of 24 to 54 carbon atoms, etc. These polybasic acids may contain certain levels of impurities (i.e. monomers, tetramers, etc.) while still suitable for use However, too high a level of monomers (about 25% or more) harms

inhibiting corrosion.

  Polyalcohols suitable for use in producing the inhibitor include, but are not limited to, the following alcohols ethylene glycol diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, pentaerythritol, trimethylolpentane, and sorbitol. Combinations of these polyalcohols may also be suitable. It is understood that these lists are representative and it will be apparent to those skilled in the art that various other polybasic acids and polyalcohols can be used. Consequently, one can consider as forming part of this invention

  other polybasic acids and other polyalcohols suitable

  nant to be used in the reaction, when they are

  used with the composition of matter described below.

  Metal hydroxides and metal oxides suitable for use in the production of the inhibitor include derivatives of lithium, potassium and

sodium.

  Surfactants suitable for use with the inhibitor include, but are not limited to, the following: (a) fatty acid ethoxylates having a chemical structure of: o Ci TCO (CHZ C Hz NH in which N is an integer between 4 and 20; (b) nonylphenol ethoxylates having a chemical structure of: C 9 O (CH 2 CH 2 O) n -H in which N is an integer between 4 and 20; (c) Alcoholic ethoxylates having a chemical structure of:

R O (CHZ CHZ H

  wherein R is C 12-C 18 and N is an integer between 4 and 20; and (d) dodecylbenzenesulfonates having a chemical structure of:

CS '

c 12

  in which X is a metal, an amine or ammonia.

  Depending on the dispersibility or solubility in

  water from the corrosion inhibitor and depending on the environment

  reason in which it is to be used, formulas for

  suitable vehicle solvents may contain hydrocarbons

bures, water and / or alcohols.

  It is within the skill of the art to use a condensation reaction to produce an ester with a desired degree of esterification. The condensation reaction to produce a partial ester can be carried out in a temperature range of 165 at 2380 C until the water from

  reaction is eliminated The ionic reaction with an imidazo-

  line (or the like) to produce the salified partial ester can be carried out in a temperature range of 38 to 94 C for a period of between 0.5 and 2.0 hours The ionic reaction with the metal hydroxide (or analog) to further salify the partial ester can be conducted in a temperature range of 38 to 940 C for a

  period between 0.5 and 2.0 hours.

  The following examples are given to further illustrate the present invention and should not be construed as limiting it.

EXAMPLE 1

  A petroleum-soluble and highly dispersible corrosion inhibitor is produced by the following method. 92.0% by weight of DTC-195 is charged to a clean reactor (DTC-195 is a 95% polymer formula comprising a fatty acid dimerized to 36 carbon atoms and a fatty acid trimerized to 54 carbon atoms in a ratio of 2: 1, manufactured by Westvaco) 7.5% by weight of diethylene glycol are added to DTC-195, while stirring and 0.5% by weight of paratoluenesulfonic acid (which is a well-known catalyst for condensation reactions) The solution is slowly heated to a maximum temperature of about 1710 C. When water begins to form at about 1150 C, it is important to carry out a sufficient nitrogen sweep to remove the water from the reactor The maximum temperature is maintained for approximately 1 hour (until the condensation reaction is brought to an end) cool the corrosi inhibitor we (hereinafter referred to as CI-N 1) before removing it from the reactor For testing purposes, the various quantities of CI-N 1 are incorporated into an inhibitor formula

  standard corrosion (hereinafter referred to as CIF-N 1)

nant:

19.2% CI-N O 1

  , 8% Witcamine 209 (imidazoline formulated from a 1: 1 molar ratio of tall oil fatty acids and diethylenetriamine, manufactured by Witco, Inc) 3.0% isopropanol 2.0% Witconate 605 A (calcium dodecylbenzenesulfate petroleum soluble, manufactured by Witco, Inc), 0% HANS (Heavy Aromatic Naphtha Solvent: solvent for

heavy aromatic naphtha).

  The test procedures on this corrosion inhibitor (and on all corrosion inhibitors tested) were carried out in a crown furnace, which provides a temperature

  and a constant speed of rotation of the exchanging bottles

  This simulates conditions at the bottom of the well with both oil and water environments and high temperatures. In normal test procedures, CO 2 is bubbled through a solution of sea salt and kerosene up to at saturation Metal samples are cleaned in acetone, dried and placed in the test bottles. The corrosion inhibitor is then added to the bottles. The bottles are washed for several minutes with C 02 and equal amounts of kerosene and salt water The bottles are closed, placed in a crown oven and they rotate 3600 to be sure that each end of the metal sample is exposed to both aqueous and petroleum environments. treatment for 1 to 2 hours at 650 C, the samples are

  removed and placed in a second set of bottles containing

  with kerosene and salt water These bottles are rotated for 1 hour; the samples are removed a second time and again placed in a mixture of kerosene and salt water and they rotate at 650 ° C. for 22 hours to check the final persistence of the film When the treatment is finished, the metal samples are removed from the bottles, rinsed in a mixture of water and hydrochloric acid concentrated in equal parts by volume, containing an additional acid corrosion inhibitor, they

  are rinsed first in distilled water and final-

  in isopropyl alcohol The metal samples are then dried by manual wiping They are weighed

  and the protection percentage is calculated according to the equa-

  tion:% protection = A-B x 100 A = weight loss of blank samples

  B = weight loss of the inhibited samples.

  The results are shown in Table 1 below.

  CIF N 1 lm% protection 750 ppm 1500 ppm 2500 ppm CIF-N I without A 85.7 9410 9415

CIF-N I + 0.25% A 8116 89; 8 93.8

CIF-N I + 0.5% A 81 t 8 91; 8 91.8

CIF- I + 1.0% A 75.8 92.1 93.4

  A) TMO-14: surfactant: tall oil monooleate with 14 moles of ethoxylate, manufactured by Stephen Chemical Company

(13.4 HLB)

  It should be noted that all the crown oven tests described in the examples are carried out in a very aqueous environment (for example, oil / water: 10/90 by volume) unless otherwise indicated. corrosion protection that the petroleum industry considers desirable is 90% or more For film persistence tests, the generally accepted industrial dosage for corrosion inhibitors (to obtain 90% protection) is 10,000 ppm, with a dosage of 5000 ppm considered as a good inhibitor and 2500 ppm considered as an excellent inhibitor We see here that either the inhibitor,

  either a combination of the inhibitor and a surfactant

  active (both with an oil-to-water ratio of: 90) gives excellent test results

  corrosion inhibiting properties.

EXAMPLE 2

  A preferred corrosion inhibitor is produced, in which 94.6% by weight of DTC-195 is reacted with 4.9% by weight

  ethylene glycol and 0.5% by weight of paratoluenesulfo- acid

  nique (as catalyst) in a condensation reaction in

  following the procedure developed in example 1 above.

  For testing purposes, various amounts of the resulting corrosion inhibitor (hereinafter referred to as CI-N 2) are incorporated into a standard corrosion inhibitor formula (hereinafter referred to as CIF-N 2), comprising: 19.4% CI-No 2.6% Witcamine 209 3.0% isopropanol 2.0% Witconate 605 A and

, 0% HANS,

  and this inhibitor is subjected to Les crown tests

  results are listed in Table 2 below.

  % of protection 750 ppm 1500 ppm 2500 ppm 5000 ppm 1000 lppm CIF-N 2 + 1 i X A89.1 94.5 95; 9 94 3 91 t 7

CIF-NO 2 + 3% A 93.8 94 W O

CIF-N 2 + 1 X B 8913 94.6 95 t 5

CIF-N 2 + 3 X B 94 X 1 9318

  A) TMO-14: surfactant: tall oil monooleate with 14 moles of ethoxylate, manufactured by Stephen Chemical Company

(13.4 HLB)

  B) MT-615: mixed tall oil acid containing 28 to 30% of rosin with 15 moles of ethoxylate, manufactured by Stephen Chemical Company (13.7 HLB) In all the cases indicated, the test results are obtained in a extremely aqueous environment (e.g. oil / water: '10: 90 by volume) The results here show excellent inhibitory properties of

corrosion).

  A comparative dispersion test is carried out between the formulas of CIF-N 1, CIF-N 2 and a conventional standard corrosion inhibition formula of polybasic acid and imidazoline. Solutions are added at 1% of the inhibitor. corrosion formulated at concentrations of 10% aqueous brine The results are shown in Table 3 below Table 35 Comparative dispersions X Dispersed Z Disperse X Dispersed Z Disperse Formula initially 15 Minutes 30 Minutes 60 Minutes

PA + I F NO DISPERSION

CIF -N 1 e 100 X 70% 30 Z

CIF -N 2 100 X 90 X 80% 30%

  PA + IF: dimer / trimer fatty acids neutralized by imidazoline.

  The standard formula of dimer / trimer acids and imidazo-

  line soluble in petroleum does not disperse in 10% aqueous brine On the contrary, the formulas CIF-N 1 and CIF-N 2 both readily disperse in brine and gradually fall out of the solution into the static system These results graphically illustrate how the choice of polyalcohols can influence the degree of

solubility of the formula.

EXAMPLE 3

  A corrosion inhibitor is prepared in which 93.9% by weight of Westvaco 1500 (a mixture of dimeric fatty acids and trimers derived from tall oil, manufactured by Westvaco) is reacted with 5.6% by weight of glycerol and 0, 5% by weight of paratoluenesulfonic acid (as catalyst) in a condensation reaction following the procedure set out in Example 1 above. For testing purposes, various amounts of the resulting corrosion inhibitor are incorporated ( hereinafter referred to as CI-N 3) in a standard corrosion inhibitor formula (hereinafter referred to as CIF-N 3) comprising:

19.2% CI-N 3

  , 8% Witcamine 209 3.0% isopropanol 2.0% Witcamine 605 A and

.0% HANS

  A traditional petroleum-soluble corrosion inhibitor is prepared for comparison by neutralizing the mixture of Westvaco 1500 dimer and trimer fatty acids with an imidazoline. This corrosion inhibitor formula includes: 12.5% Westvaco 1500 12 , 5% Witcamine 209 3.0% isopropanol 2.0% Witcamine 605 A and

.0% HANS

  Both formulas are tested on a carousel in a water and oil environment in the 90:10 ratio.

  results are listed in Table 4 below.

CI-N 3

  % protection 750 ppm 1500 ppm 2500 ppm 5000 ppm OS 60.1 44 t 6 54.7

CIF-N 3 91.5 95.7 96.1

  The results indicate that the ester-based corrosion inhibitor formula is far superior to a traditional corrosion inhibitor formula based on the same

dimer and trimer fatty acids.

EXAMPLE 4

  A corrosion inhibitor is prepared, in which 93.8% by weight of DTC-195 is reacted with 5.7% by weight of glycerol and 0.5% by weight of paratoluenesulfonic acid (as catalyst) in a reaction of condensation in

  following the procedure set out in Example 1 above.

  The inhibitor is hereinafter designated CI-No 4.

  By following the test procedure on carousel exposed in example 1, a series of comparison tests is carried out both in a water and oil environment in the 90/10 ratio and in an aqueous environment at 100 % between the equivalent amounts of a formula containing CI-N 4 highly dispersible in water, a standard petroleum soluble corrosion inhibitor formula and a standard water soluble corrosion inhibitor formula two environments, the water was turned off with brine

  NACE 10% CI-No 4 is incorporated into an inhi- formula

  standard corrosion buffer (hereinafter referred to as CIF-N 4) comprising:

19.4% CI-N 4

  5.6% Witcamine 209 3.0% isopropanol 2.0% Witconate 605 A and

.0% HANS

  The petroleum soluble corrosion inhibitor (OSF) formula includes: 12.5% DTC-295 (a mixture of polymerized dimer / trimer fatty acids, manufactured by Westvaco) 12.5% Witcamine 209 3.0% isopropanol 2.0% Witconate 605 A, and

.0% HANS

  The water soluble corrosion inhibitor (WSF) formula includes:, 0% JETCO S-50 (a quaternary ammonium compound manufactured by Jetco, Inc) 32.0% isopropanol 18.0% water

  The results are shown in the respective Tables below.

after.

Table 6

  : I 0 water: petroleum Comparison pp Mn OSF CIF'N 4 WSF 750 92.7 93 r 5 <25 X O

1500 94.0 93.0 <25.0

2500 92.0 93.2 <250

5000 <25 t O

Table 7

  % water Comparison pp M OSF CIF-N 4 WSF

750 65; 0 74 X 1 <2570

1500 66 t 6 7974 <25 t O

2500 70.5 84.3 <25; O

  5000 75 W 2 85 t 8 <25 O When compared to the petroleum soluble formula

  in the dynamic carousel test environment, CIF-

  N 4 has equivalent corrosion inhibition properties in the water and hydrocarbon environment and superior inhibition properties in the aqueous environment In a dynamic test, the formula CIF-N 4 is far superior in both environments compared to the water-soluble formula (including protection against

  corrosion is always less than 25%).

EXAMPLE 5

  A corrosion inhibitor highly dispersible in water and soluble in petroleum is prepared by the following method. 93.5% by weight of DTC-195 is loaded into a clean reactor (DTC-195 is a 95% polymer formula comprising a fatty acid dimerized to 36 carbon atoms and a fatty acid trimerized to 54 carbon atoms in a ratio of 2 to 1, manufactured by Westvaco) is added, with stirring, to DTC-195,

  0.69% by weight of ethylene glycol, 1.88% by weight of diethylene

  leneglycol, 1.88% by weight of glycerol, 1.88% by weight of

  trimethanol propane and 0.2% by weight of paratoluenesul acid

  The solution is slowly heated to a maximum temperature of approximately 193 ° C. As water begins to form at approximately 1500 ° C., it is important to rinse with sufficient nitrogen to remove the water from the reactor. The maximum temperature is maintained for approximately 1 hour (or until the end of the condensation reaction)

  cool the corrosion inhibitor (hereinafter referred to as CI-

  N O 5) before removing it from the reactor CI-No 5 is incorporated

  porous in a corrosion inhibitor formula (designated below)

after CIF-N O 5) including

19.2% CI-N O 5

  , 8% Witcamine O 209 3.0% isopropanol 2.0% Witconateg 605 A

.0% HANS

  The CIF-N O 5 formula gives excellent results during the tests. Although, in the examples above, the various corrosion inhibitors were formulated for dynamic environments, and tested in these environments, corresponding to the severe conditions encountered in the practice of drilling wells, it should be noted that the inhibitors also function well. to prevent corrosion when used in other, usually less severe, applications (eg oil and gas pipelines, finished product pipelines, car radiators, etc.)

  many modifications and variations of this invention

  tion will appear to those skilled in the art in the light of the teaching

  above above It is therefore understood that the scope of

  the invention is not limited by the preceding description.

Claims (13)

Claims   1. Composition of matter, characterized in that it has the following general chemical structure: A) c H 3 (CHZ) 5 () 7 c-O CH 3 C O-z + or O B) CH 3 (CH 2) 5 (CH 2) 7 -C Z + (C 2) 5 (c 2) 7 CH 3 CO   OR in which R is a polyalcohol and Z + is an element from the group comprising an imidazoline, fatty diamines or their combinations.   2. Composition of matter according to claim 1, character-   laughed at in that the polyalcohol is chosen from the group   including the following alcohols: ethylene glycol, diethylene-   glycol, triethylene glycol, polyethylene glycol, glycerin, sorbitol, pentaerythritol, trimethylolpentane and combinations thereof   3 Composition of matter according to claim 1, character-   laughed at by the fact that imidazoline, fatty diamines or their combinations are reacted with an element chosen from the   group comprising a metal hydroxide, a metal oxide   that, ammonia or combinations thereof.   4. Method for producing a corrosion inhibitor, characterized in that it comprises the following stages: (a) reacting in a condensation reaction a polybasic acid with a polyalcohol to form a partial ester which is esterified at 35 to 71% ; and (b) reacting in an ionic reaction this partial ester with 15 to 32% by weight of an element chosen from the group comprising an imidazoline, fatty diamines, or their combinations, thus salifying the partial ester to form a corrosion inhibitor.   5. Method according to claim 4, characterized in that it comprises the following stages: (a) reacting in a condensation reaction a polybasic acid with a polyalcohol to form a partial ester which is esterified at 45 to 60%; and (b) reacting in an ionic reaction this partial ester with 18 to 28% by weight of an element chosen from the group comprising an imidazoline, fatty diamines or their combinations, thus salifying the partial ester to form a corrosion inhibitor.   6. Method according to claim 4, characterized in that the salified partial ester is reacted in an ionic reaction with 5 to 10% by weight of an element chosen from the group comprising a metal hydroxide, a metal oxide, l or combinations thereof, further salifying   partial ester to form a corrosion inhibitor.   7. Method according to claim 4, characterized in that the polybasic acid is chosen from the group comprising fatty acids dimerized to 16 to 36 carbon atoms, acids   fat trimerized to 24 to 54 carbon atoms and their combinations   nons. 8. Method according to claim 4, characterized in that the polyalcohol is chosen from the group comprising:   following alcohols: ethylene glycol, diethylene glycol, triethyl-   lene glycol, polyethylene glycol, glycerin, sorbitol, penta-   rythritol, trimethylolpentane, and combinations thereof. 9. Method according to claim 6, characterized in that the metal contained in the metal hydroxide or the metal oxide is chosen from the group containing lithium, potassium, and sodium.   10. Method according to one of claims 4 to 6, character-   laughed at by using a surfactant or a combination of surfactants mixed with it corrosion inhibitor.   11. The method of claim 10, wherein the surfactant is chosen from the group comprising: (a) fatty acid ethoxylates having the following chemical structure: IC 17 co (C Hz CH 2) n H in which N is an integer between 4 and 20; (b) nonylphenol ethoxylates having the following chemical structure: C 9 (CH 2 CH 2 0) H   wherein N is an integer between 4 and 20; (c) alcohol ethoxylates having the following chemical structure: R O (CH 2 CH 2 O) M H   wherein R is C 12-C 18 and N is an integer between 4 and 20; (d) dodecylbenzenesulfonates having the following chemical structure Cdz z SO 3 x in which X is a metal, an amine or ammonia; and (e) their combinations.   12. Product of the process according to claim 4, characterized in that the product is a very corrosion inhibitor   dispersible in water and soluble in petroleum.   13. Product of the process according to claim 4, characterized in that the product is a soluble corrosion inhibitor   in water and dispersible in petroleum.   14. Product of the process according to one of claims 6 to   10. 15 Method for inhibiting corrosion in the equipment and pipelines of an oil field, which are in contact with an oil and water medium leaving a production well, characterized in that this is coated equipment and these pipes with a formula including the inhibitor of   corrosion of the process of one of claims 4 to 10.   16. Method according to claim 15, characterized in that   a vehicle solvent is added to disperse the inhibitor.   17 Method according to claim 16, characterized in that the vehicle solvent is chosen from the group comprising water, an alcohol, solvents based on hydrocarbons and their combinations.   18 Method for inhibiting corrosion in metals which are in contact with an aqueous medium, characterized in that   that the metal is coated with a formula comprising the compound   tion of materials of one of claims 1 to 3.